Baking ovens of the above type are disclosed in German Published Application OS No. 14 32 916 and U.S. Pat. No. 3,412,695. In these baking ovens, the chain of the drive of the turntable extends, without a seal, from the baking compartment and is wrapped around the freely exposed pinion of the drive shaft.
The known embodiments of the turntable drive do not satisfy the requirements of baking ovens of the aforementioned type, also known as baking cabinets.
In this regard, it is necessary for a baking cabinet, in the same way as for all baking ovens, for the baking compartment to be tightly closed off from the surrounding atmosphere so that no vapor, condensate or lubricant can pass into the baking compartment. The possibility of emergence of vapor, etc. is, however, present in the aforementioned known baking cabinets, in which an ordinary opening is provided, for the passage of the chain, in the wall surrounding the baking compartment. The emergence of vapor at this location can furthermore not be prevented by arranging the passage of the chain below the turntable, since the vapor passes through the gap required for movement between the periphery of the turntable and the surrounding false bottom and also into the space located below the turntable. This space represents a part of the baking compartment insofar as there prevails within it substantially the same atmospheric conditions as in the rest of the baking compartment within which is located the material to be baked.
The vapor escaping at the location of passage of the chain constitutes a loss of energy and thus reduces the economy of the baking process. Condensation of the vapor on the walls and equipment of the baking compartment promotes the formation of mold thereat. Furthermore, vapor can penetrate from the opening for the passage of the chain into the space filled with insulating material between the wall of the baking compartment and the outer covering of the baking oven, resulting in damage by corrosion and impairment of the insulating action. Finally, the region surrounding the drive shaft becomes considerably filthy as a result of the required lubrication of the chain.